Prior to the instant invention, plating of aluminum with a bond-promoting metal, such as nickel and/or cobalt, was accomplished by a variety of methods. Included in the prior methods were plating techniques which employed acidic plating media, as for example, the technique set forth in U.S. Pat. No. 1,837,835. Also, a conventional electroless deposition from a hypophosphite solution is set forth in U.S. Pat. No. 2,532,283. The latter deposition provides bright coatings having aesthetic appeal, however, these coatings are inferior to those coatings provided by thermal decomposition or vacuum deposition processes when the coating is to be used in a bonding step. Thus, when a coated part prepared by conventional plating methods is employed in a subsequent bonding operation, the bond produced is often inadequate.
U.S. Pat. No. 3,482,305 discloses a brazing method wherein a bond-promoting metal is used in conjunction with the brazing of aluminum. The instant invention utilizes an improved bond-promoting plating where the plated aluminum article is to be bonded to another metal article, such as by brazing of aluminum, and optimizes the bonding process.